The nation's sole manufacturer of the West Nile Virus vaccine said Thursday that it can meet any increase in demand -- including in Minnesota, where the disease was detected earlier this week in two crows.

"We've increased our forecasts for the production of the vaccine and feel confident we will be able to meet the needs of veterinarians and horse owners," said Rob Daily, director of the equine business unit for Fort Dodge Animal Health, a Kansas-based division of Wyeth Inc.

Fort Dodge Animal Health received a conditional license from the FDA last year to market the vaccine as the West Nile Virus spread from New York to Florida and more than 30 other states. The virus is carried by more than 100 species of birds and is spread by mosquitoes to humans and horses.

Horses are most susceptible, with at least 738 being diagnosed with the disease in other states last year. About a third of those horses died or had to be euthanized, officials said.

So far, 56 U.S. horses have been diagnosed with the virus this year, the government said.

After Wednesday's news that the virus has entered Minnesota, veterinarians reported receiving calls from horse owners who are requesting vaccinations for their animals. While many of the horses in the state's big barns have been vaccinated, thousands of other Minnesota horses remain unvaccinated.

Daily said his company has sold 87,000 doses of the vaccine to Minnesota veterinarians and distributors this year. The vaccine is distributed in two doses administered three to six weeks apart. A third booster is to be given a year later.

Considering the double doses, Daily said, Minnesota has enough vaccine to cover about 43,500 horses. But there are more than 57,000 ponies and horses in the state, said Michael Hunst of the Minnesota Agricultural Statistics Service. That figure underestimates the true number, Hunst said, because small hobby farms were not included in the latest statistics available -- a 1997 census of working farms.

Minnesota is the 35th state to find the virus in birds, horses or people, experts say. There is no vaccine for humans. The arrival of the virus in a state typically sparks a run on horse vaccinations, Daily said.

"The imminent threat goes way up, and people tend to call their veterinarians to schedule their vaccinations," Daily said. "But waiting until it's in your area doesn't afford every horse the opportunity to get the protection it needs."

In Woodbury, Mark and Marcia Ward, owners of Windy Ridge riding stable, vaccinated last spring. Mark Ward said they paid about $20 per shot for the series. "It's about twice as much as any other vaccine that we've ever given a horse," he said.

The efficacy of the vaccine is not yet known because studies aren't complete. But out of millions of doses administered, only five horses have contracted the virus, Daily said.

The FDA approved Fort Dodge's conditional license because of the spreading disease. Daily said that when the company is fully licensed, horse owners will be able to administer the vaccinations themselves rather than being required to hire a veterinarian.

Fort Dodge Animal Health, which manufacturers the vaccine in Iowa, has annual sales of $600 million. Its New Jersey-based parent company, Wyeth -- formerly named American Home Products -- makes pharmaceuticals and health care products including Advil and Robitussin.

-- Joy Powell is at jpowell@startribune.com.